Methods for isolating DNA, RNA, and proteins from complex biological samples are some of the most crucial steps in molecular biology and magnetic particles are a key tool for analyte (e.g., DNA, RNA, Cells) isolation and sample preparation. The ability to use functionalized paramagnetic particles (PMPs) to isolate analytes of interest has expanded the utility of isolation methods across a range of platforms. Typically, the magnetic separation process typically involves mixing the sample with paramagnetic particles in a liquid medium to bind the target substance by affinity reaction, and then separating the bound particle/target complex from the sample medium by applying a magnetic field.
Siddiqi, U.S. Pat. No. 6,500,343 discloses an apparatus and method for carrying out the affinity separation of a target substance from a liquid test medium by mixing magnetic particles having surface immobilized ligand or receptor within the test medium to promote an affinity binding reaction between the ligand and the target substance. The test medium with the magnetic particles in a suitable container is removably mounted in an apparatus that creates a magnetic field gradient in the test medium. This magnetic gradient is used to induce the magnetic particles to move, thereby effecting mixing. The mixing is achieved either by movement of a magnet relative to a stationary container or movement of the container relative to a stationary magnet. In either case, the magnetic particles experience a continuous angular position change with the magnet. Concurrently with the relative angular movement between the magnet and the magnetic particles, the magnet is also moved along the length of the container causing the magnetic field gradient to sweep the entire length of the container. After the desired time sufficient for the affinity reaction to occur, movement of the magnetic gradient is ended, whereby the magnetic particles are immobilized on the inside wall of the container nearest to the magnetic source. The remaining test medium is removed while the magnetic particles are retained on the wall of the container. The test medium or the particles may then be subjected to further processing.
It can be appreciated that some affinity separation processes, as heretofore described, may be conducted in “sticky” mediums, thereby causing the magnetic particles to clump together and stick to surfaces (e.g., the side of a tube, face of a plate). The clumps of magnetic particles inevitably capture contaminants, which inhibit downstream analysis (e.g., nanodrop DNA quantification, PCR, etc.). Further, due to the stickiness of the clump, it may be difficult to break up the aggregate of the magnetic particles. As such, in order to break up the aggregate of the magnetic particles, the external agitation of the magnetic particles through pipetting is often required. However, the external agitation of the magnetic particles is not always effective, increases chances of sample loss, and adds time to the sample preparation process.
Therefore, it is a primary object and feature of the present invention to provide a method and a device for the disaggregation of particles in a fluidic medium to facilitate the downstream analysis of an analyte.
It is a further object and feature of the present invention to provide a method and a device for the disaggregation of particles in a fluidic medium to facilitate the downstream analysis of an analyte which reduces and/or eliminates use of external agitation with a pipette.
It is a still further object and feature of the present invention to provide a method and a device for the disaggregation of particles in a fluidic medium to facilitate the downstream analysis of an analyte which is inexpensive and simple.
In accordance with the present invention, a method is provided of reducing the clumping of a plurality of solid phase substrate as the plurality of solid phase substrate are transferred from a first location to a second location. Each solid phase substrate has a dimension. The method includes the step of depositing the plurality of solid phase substrate at the first location. A plurality of particles is added to the plurality of solid phase substrate. Each of the plurality of particles may have a dimension greater than the dimensions of the plurality of solid phase substrate. A force is generated to draw the plurality of solid phase substrate from the first location to a second location. The plurality of particles cause at least a portion of the plurality of solid phase substrate to separate from each other as the plurality of solid phase substrate is drawn from the first location to the second location.
The plurality of particles may be magnetic and the force generated may be a magnetic force. Alternatively, the plurality of particles may be non-magnetic. The plurality of solid phase substrate may be magnetic beads and the plurality of particles may be generally spherical. The step of adding the plurality of particles to the plurality of solid phase substrate may occur prior to the step of depositing the plurality of solid phase substrate at the first location.
In accordance with a further aspect of the present invention, a method is provided of reducing the clumping of a plurality of solid phase substrate as the plurality of solid phase substrate are transferred from a first location to a second location. The method includes the steps of depositing the plurality of solid phase substrate at the first location and adding a plurality of particles to the plurality of solid phase substrate to form a mixture. A force is generated to draw the mixture from the first location to a second location. The force causes the plurality of particles of the mixture to travel to the second location at a velocity greater than a velocity at which the plurality of solid phase substrate of the mixture travels to the second location.
The plurality of particles may be magnetic and the force generated may be a magnetic force. Alternatively, the plurality of particles may be non-magnetic. The plurality of solid phase substrate may be magnetic beads and the plurality of particles may be generally spherical. The step of adding the plurality of particles to the plurality of solid phase substrate may occur prior to the step of depositing the plurality of solid phase substrate at the first location. Each of the plurality of particles has a dimension and each of the plurality of solid phase substrate has a dimension. The dimensions of the plurality of particles may be greater than the dimensions of the plurality of solid phase substrate.
In accordance with a still further aspect of the present invention, a device is provided for facilitating the isolation of targets from a biological sample. The device includes a plurality of solid phase substrate. The targets are bindable to the plurality of solid phase substrate and the plurality of solid phase substrate are movable in response to a magnetic force. A plurality of particles are addable to the plurality of solid phase substrate. The plurality of particles break apart clumps of the plurality of solid phase substrate as the plurality of solid phase substrate are moved in response to the magnetic force.
Each of the plurality of particles has a dimension and each of the plurality of solid phase substrate has a dimension. The dimensions of the plurality of particles may be greater than the dimensions of the plurality of solid phase substrate. Each of the plurality of particles has an outer surface and a coating about the outer surface. The coating may be magnetic. The plurality of solid phase substrate may be magnetic beads and the plurality of particles may be generally spherical.